| 摘要 |
<p>The invention relates to a high sensitivity fault current protection switch, responding to any current, which is used particularly in domestic electrical installation technology and consumer networks. The circuit is used for the detection of fault currents of any wave form and for the detection of low resistance connections between the neutral and protective earth lines in the load. In this case, a frequency generated by a clock generator (1) is fed to the secondary winding (3) of a summing current transformer (2), the output of which is connected to a voltage divider (6), by means of which the clock current is made symmetrical. The pulsed signal is passed to a comparator circuit (7, 8) via a winding tapping (4), the pulsed signal being compared with in each case one reference voltage. If the signal is too high and/or too low, the comparators (7) and/or (8) switch on, thus activating the trip relay (12). An RC element (10) with a downstream comparator (11) is used for intercepting parasitic interference peaks. <IMAGE></p> |
